''' <summary>
''' Embeds specified file into specified PDF document.
''' </summary>
''' <param name="pdfFilename">The filename of PDF document.</param>
''' <param name="embeddingFilename">The filename of embedding file.</param>
Public Shared Sub EmbedFileIntoPdfDocument(pdfFilename As String, embeddingFilename As String)
    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        ' if embedded files are absent
        If document.EmbeddedFiles Is Nothing Then
            ' create new dictionary
            document.EmbeddedFiles = New Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFileSpecificationDictionary(document)
        End If

        ' create embedded file instance
        Dim embeddedFile As New Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFile(document, embeddingFilename, Vintasoft.Imaging.Pdf.PdfCompression.Zip)
        ' create embedded file specification
        Dim fileSpecification As New Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFileSpecification(embeddingFilename, embeddedFile)
        ' set description of the embedded file specification
        fileSpecification.Description = "Test embedding"
        ' add the embedded file specification to the dictionary
        document.EmbeddedFiles.Add(embeddingFilename, fileSpecification)
        ' save changes to the source
        document.SaveChanges()
    End Using
End Sub

/// <summary>
/// Embeds specified file into specified PDF document.
/// </summary>
/// <param name="pdfFilename">The filename of PDF document.</param>
/// <param name="embeddingFilename">The filename of embedding file.</param>
public static void EmbedFileIntoPdfDocument(string pdfFilename, string embeddingFilename)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
    {
        // if embedded files are absent
        if (document.EmbeddedFiles == null)
            // create new dictionary
            document.EmbeddedFiles = 
                new Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFileSpecificationDictionary(document);

        // create embedded file instance
        Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFile embeddedFile = 
            new Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFile(
                document, embeddingFilename, Vintasoft.Imaging.Pdf.PdfCompression.Zip);
        // create embedded file specification
        Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFileSpecification fileSpecification = 
            new Vintasoft.Imaging.Pdf.Tree.PdfEmbeddedFileSpecification(embeddingFilename, embeddedFile);
        // set description of the embedded file specification
        fileSpecification.Description = "Test embedding";
        // add the embedded file specification to the dictionary
        document.EmbeddedFiles.Add(embeddingFilename, fileSpecification);
        // save changes to the source
        document.SaveChanges();
    }
}